Monday, August 19, 2013

White Deposits on Avocado Trunks

What causes the white exudate on avocado trunk and branches?

When avocado trees are wounded, tree sap oozes out. The white residue seen on tree trunks is simply the sugars left behind as the water from the sap evaporates. The wounds can be made by just about anything including poking holes with a knife or nail and insects trying to bore into the tree. 

There are also a few avocado diseases, caused by fungi and bacteria, which will result in wounds that ooze leaving a white residue. In areas of heavy rainfall the sugars are not always visible as they may be washed away. 

Although not a major pest of avocados, one invader which will leave small amounts of white residue is the black twigborer.

Search black twigborer on this website for more information on this pest.

Photos from Topics in Subtropics,by  Dr. Ben Faber